1. Field of the Invention
The present invention relates to chemical reactants, compositions, methods to manufacture reactants, and apparatus for the generation of a gas pressure to drive a fluid from an infusion pump.
2. Background of the Art
There are several examples in the art of infusion pumps which operate on the use of gas pressure to drive an infusion liquid into a patient. For example, in Baron, U.S. Pat. No. 4,379,453, an infusion bag is equipped with an internal bag including a set of reactive chemicals that when mixed react to form a gas and inflate the internal bag to drive a liquid from the infusion bag. Similarly, in Baron, U.S. Pat. No. 4,379,453 the inventor disposed the reactive chemicals into a cuff-like apparatus to squeeze the liquid from the infusion bag.
The use of gas pressure, without the need for a chemical reaction, has also been demonstrated. See U.S. Pat. No. 5,106,374.
However, in each of the above-described patents, there is a limited ability for an operator to control the pressure of the gas and ultimately the flow rate of the liquid from the device. Baron in U.S. Pat. No. 4,379,453 attempted to solve this problem by utilizing a plurality of reactions. However, this system merely creates two "peaks" in pressure and consequently flow rate.
Accordingly, a need exists in the art for controlled rate infusion devices which can be retrieved through the use of reactive chemicals to generate gas.